Gauging Sea-Level Rise at Five Refuges

Five national wildlife refuges, the Refuge System Inventory and Monitoring program, the U.S. Geological Survey, NOAA’s Tijuana River National Estuarine Research Reserve, a handful of other partners and two landscape conservation cooperatives (LCCs) are collaborating on a project along the California coastline that illustrates how LCCs might routinely work on a practical level in the not-too-distant future.

With guidance from Pacific Southwest Region Refuge System I&M specialist Giselle Block, the California LCC and the North Pacific LCC are teaming up on a sea-level rise modeling project at points roughly 800 miles apart along the Pacific Coast – from Humboldt Bay National Wildlife Refuge on the north to Tijuana Slough Refuge on the south, with San Pablo, Seal Beach and San Diego Bay Refuges in between.

The project, which runs through September 2013 and is expected to cost roughly $300,000, is designed to foster “a bottom-up approach to evaluating sea-level rise effects” at a local scale relevant to the landscape level. It is doing so by developing high-resolution digital elevation models (DEMs); monitoring water levels and tidal cycles to assess local-level inundation patterns; inventorying vegetation species composition and relationship to elevation and tides; and quantifying sensitive wildlife use at all five refuges.

It would have been difficult to pull off without the two LCCs, which are part of the national network of 22 public-private partnerships designed to transcend jurisdictional boundaries and provide a holistic, collaborative, adaptive approach to conservation that is grounded in science.

Without the LCCs, “it is unlikely that we would have obtained funding to conduct work at such a broad spatial scale,” says Block. “Because LCCs work at larger spatial scales, we were able to work at sites that span the Pacific Coast using a consistent set of methods and an analytical approach.”

That consistency will provide refuge managers with information that is relevant to their immediate locale and also is applicable on a landscape level. It will permit valid ecosystem comparisons up and down California. “By working with the LCCs,” says Block, “we are able to examine tidal marsh ecosystems along the entire coast, allowing us to identify major similarities and differences in elevation, plant communities and vulnerability to sea-level rise and extreme flooding events.”

Mary Mahaffy – interim coordinator of the North Pacific LCC, which is funding the Humboldt Bay Refuge portion of the project – says the LCC concept is “important because it’s a different way of doing business than we’ve done in the past.”

LCCs, she says, “allow parallel efforts among agencies to work together on environmental stressors that are too great for any one agency or organization to do alone.” LCCs will help create “a common base” and deliver science information and tools to managers so they can make more informed decisions 10 to 25 years out.

Two major benefits of this project, according to San Diego Bay Refuge manager leader Andy Yuen, are its level of detail and its permanence. Unlike SLAMM (Sea Level Affecting Marshes Model), which Yuen called “more of a broad brush” that uses existing data, this study is collecting new data and “taking it down to a new level of detail” – to an individual-parcel scale. Furthermore, he says, this project is “putting in permanent benchmarks, so we’ll be able to precisely measure sea-level rise” for years to come.

Beyond that, says Block, the Refuge System I&M program will use the project’s data and findings “to support the needs of refuges relative to sea-level rise, specifically subjects such as adaptation planning and climate monitoring. They will also be used to identify how best to approach modeling in the future and at other estuarine refuge holdings along the Pacific Coast.”

All of this is crucial because, says Yuen, many of his refuge’s species – including the endangered California least tern, the endangered light-footed clapper rail and the threatened western snowy plover – live and nest on “on beaches that are inches to feet above sea level.”

By Bill O’Brian. This article originally appeared in the November/December issue of Refuge Update.